Smart meter

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Smart_meter 

 

Example of a smart meter based on Open smart grid protocol (OSGP) in use in Europe that has the ability to reduce load, disconnect-reconnect remotely, and interface to gas and water meters.

 

Newer retrofitted U.S. domestic digital electricity meter Elster REX with 900MHz mesh network topology for automatic meter reading and "EnergyAxis" time-of-use metering.

 

Each local mesh networked smart meter has a hub such as this Elster A3 Type A30, which interfaces 900MHz smart meters to the metering automation server via a landline.

 

Itron OpenWay electricity Smart meter with two-way communications for remote reading in use by DTE Energy

A smart meter is an electronic device that records information such as consumption of electric energy, voltage levels, current, and power factor. Smart meters communicate the information to the consumer for greater clarity of consumption behavior, and electricity suppliers for system monitoring and customer billing. Smart meters typically record energy near real-time, and report regularly, short intervals throughout the day. Smart meters enable two-way communication between the meter and the central system. Such an advanced metering infrastructure (AMI) differs from automatic meter reading (AMR) in that it enables two-way communication between the meter and the supplier. Communications from the meter to the network may be wireless, or via fixed wired connections such as power line carrier (PLC). Wireless communication options in common use include cellular communications, Wi-Fi (readily available), wireless ad hoc networks over Wi-Fi, wireless mesh networks, low power long-range wireless (LoRa), Wize (high radio penetration rate, open, using the frequency 169 MHz) Zigbee (low power, low data rate wireless), and Wi-SUN (Smart Utility Networks).

Overview

The term Smart Meter often refers to an electricity meter, but it also may mean a device measuring natural gas, water or district heating consumption.

Similar meters, usually referred to as interval or time-of-use meters, have existed for years, but "Smart Meters" usually involve real-time or near real-time sensors, power outage notification, and power quality monitoring. These additional features are more than simple automated meter reading (AMR). They are similar in many respects to Advanced Metering Infrastructure (AMI) meters. Interval and time-of-use meters historically have been installed to measure commercial and industrial customers, but may not have automatic reading.

Research by the UK consumer group, showed that as many as one in three confuse smart meters with energy monitors, also known as in-home display monitors.

The installed base of smart meters in Europe at the end of 2008 was about 39 million units, according to analyst firm Berg Insight. Globally, Pike Research found that smart meter shipments were 17.4 million units for the first quarter of 2011. Visiongain determined that the value of the global smart meter market would reach US$7 billion in 2012.

As of January 2018, over 99 million electricity meters were deployed across the European Union, with an estimated 24 million more to be installed by the end of 2020. The European Commission DG Energy estimates the 2020 installed base to have required €18.8 billion in investment, growing to €40.7 billion by 2030, with a total deployment of 266 million smart meters.

By the end of 2018, the U.S. had over 86 million smart meters installed. In 2017, there were 665 million smart meters installed globally. Revenue generation is expected to grow from $12.8 billion in 2017 to $20 billion by 2022.

Smart meters may be part of a smart grid, but do not themselves constitute a smart grid.

Brief history

In 1972, Theodore Paraskevakos, while working with Boeing in Huntsville, Alabama, developed a sensor monitoring system that used digital transmission for security, fire, and medical alarm systems as well as meter reading capabilities. This technology was a spin-off from the automatic telephone line identification system, now known as Caller ID.

In 1974, Paraskevakos was awarded a U.S. patent for this technology. In 1977, he launched Metretek, Inc., which developed and produced the first smart meters. Since this system was developed pre-Internet, Metretek utilized the IBM series 1 mini-computer. For this approach, Paraskevakos and Metretek were awarded multiple patents.

Purpose

Since the inception of electricity deregulation and market-driven pricing throughout the world, utilities have been looking for a means to match consumption with generation. Non-smart electrical and gas meters only measure total consumption, providing no information of when the energy was consumed. Smart meters provide a way of measuring electricity consumption in near real-time. This allows utility companies to charge different prices for consumption according to the time of day and the season. It also facilitates more accurate cash-flow models for utilities. Since smart meters can be read remotely, labor costs are reduced for utilities.

Smart metering offers potential benefits to customers. These include, a) an end to estimated bills, which are a major source of complaints for many customers b) a tool to help consumers better manage their energy purchases—smart meters with a display outside their homes could provide up-to-date information on gas and electricity consumption and in doing so help people to manage their energy use and reduce their energy bills. With regards to consumption reduction, this is critical for understanding the benefits of smart meters because the relatively small percentage benefits in terms of savings are multiplied by millions of users. Smart meters for water consumption can also provide detailed and timely information about customer water use and early notification of possible water leaks in their premises. Electricity pricing usually peaks at certain predictable times of the day and the season. In particular, if generation is constrained, prices can rise if power from other jurisdictions or more costly generation is brought online. Proponents assert that billing customers at a higher rate for peak times encourages consumers to adjust their consumption habits to be more responsive to market prices and assert further, that regulatory and market design agencies hope these "price signals" could delay the construction of additional generation or at least the purchase of energy from higher-priced sources, thereby controlling the steady and rapid increase of electricity prices.

An academic study based on existing trials showed that homeowners' electricity consumption on average is reduced by approximately 3-5% when provided with real-time feedback.

Another advantage of smart meters that benefits both customers and the utility is the monitoring capability they provide for the whole electrical system. As part of an AMI, utilities can use the real-time data from smart meters measurements related to current, voltage, and power factor to detect system disruptions more quickly, allowing immediate corrective action to minimize customer impact such as blackouts. Smart meters also help utilities understand the power grid needs with more granularity than legacy meters. This greater understanding facilitates system planning to meet customer energy needs while reducing the likelihood of additional infrastructure investments, which eliminates unnecessary spending or energy cost increases.

Though the task of meeting national electricity demand with accurate supply is becoming ever more challenging as intermittent renewable generation sources make up a greater proportion of the energy mix, the real-time data provided by smart meters allow grid operators to integrate renewable energy onto the grid in order to balance the networks. As a result, smart meters are considered an essential technology to the decarbonisation of the energy system.

Technology

Connectivity

Communication is a critical technological requirement for smart meters. Each meter must be able to reliably and securely communicate the information collected to a central location. Considering the varying environments and places where meters are found, that problem can be daunting. Among the solutions proposed are: the use of cell and pager networks, satellite, licensed radio, combination licensed and unlicensed radio, and power line communication. Not only the medium used for communication purposes, but also the type of network used, is critical. As such, one would find: fixed wireless, wireless mesh network and wireless ad hoc networks, or a combination of the two. There are several other potential network configurations possible, including the use of Wi-Fi and other internet related networks. To date no one solution seems to be optimal for all applications. Rural utilities have very different communication problems from urban utilities or utilities located in difficult locations such as mountainous regions or areas ill-served by wireless and internet companies.

In addition to communication with the head-end network, smart meters may need to be part of a home area network, which can include an in-premises display and a hub to interface one or more meters with the head end. Technologies for this network vary from country to country, but include power line communication, wireless ad hoc network, and Zigbee.

Protocols

ANSI C12.18 is an ANSI Standard that describes a protocol used for two-way communications with a meter, mostly used in North American markets. The C12.18 Standard is written specifically for meter communications via an ANSI Type 2 Optical Port, and specifies lower-level protocol details. ANSI C12.19 specifies the data tables that are used. ANSI C12.21 is an extension of C12.18 written for modem instead of optical communications, so it is better suited to automatic meter reading. ANSI C12.22 is the communication protocol for remote communications.

IEC 61107 is a communication protocol for smart meters published by the IEC that is widely used for utility meters in the European Union. It is superseded by IEC 62056, but remains in wide use because it is simple and well-accepted. It sends ASCII data using a serial port. The physical media are either modulated light, sent with an LED and received with a photodiode, or a pair of wires, usually modulated by EIA-485. The protocol is half-duplex. IEC 61107 is related to, and sometimes wrongly confused with, the FLAG protocol. Ferranti and Landis+Gyr were early proponents of an interface standard that eventually became a sub-set of IEC1107.

The Open Smart Grid Protocol (OSGP) is a family of specifications published by the European Telecommunications Standards Institute (ETSI) used in conjunction with the ISO/IEC 14908 control networking standard for smart metering and smart grid applications. Millions of smart meters based on OSGP are deployed worldwide. On July 15, 2015, the OSGP Alliance announced the release of a new security protocol (OSGP-AES-128-PSK) and its availability from OSGP vendors. This deprecated the original OSGP-RC4-PSK security protocol which had been identified to be vulnerable.

There is a growing trend toward the use of TCP/IP technology as a common communication platform for Smart Meter applications, so that utilities can deploy multiple communication systems, while using IP technology as a common management platform. A universal metering interface would allow for development and mass production of smart meters and smart grid devices prior to the communication standards being set, and then for the relevant communication modules to be easily added or switched when they are. This would lower the risk of investing in the wrong standard as well as permit a single product to be used globally even if regional communication standards vary.

Some smart meters may use a test IR LED to transmit non-encrypted usage data that bypasses meter security by transmitting lower level data in real-time.

Smart Meter Equipment Technical Specifications (SMETS)

In the UK, smart meters variants are classified as Smart Meter Equipment Technical Specifications (SMETS), with first generation smart meters commonly known as SMETS1 and second generation smart meters known as SMETS2.

In August 2020, smart meter installer SMS plc was the first company to fit the new three-phase SMETS2 meter – developed by Aclara Technologies – on behalf of UK energy supplier, Good Energy.

Data management

The other critical technology for smart meter systems is the information technology at the utility that integrates the Smart Meter networks with utility applications, such as billing and CIS. This includes the Meter Data Management system.

It also is essential for smart grid implementations that power line communication (PLC) technologies used within the home over a Home Area Network (HAN), are standardized and compatible. The HAN allows HVAC systems and other household appliances to communicate with the smart meter, and from there to the utility. Currently there are several broadband or narrowband standards in place, or being developed, that are not yet compatible. To address this issue, the National Institute for Standards and Technology (NIST) established the PAP15 group, which studies and recommends coexistence mechanisms with a focus on the harmonization of PLC Standards for the HAN. The objective of the group is to ensure that all PLC technologies selected for the HAN coexist as a minimum. The two leading broadband PLC technologies selected are the HomePlug AV / IEEE 1901 and ITU-T G.hn technologies. Technical working groups within these organizations are working to develop appropriate coexistence mechanisms. The HomePlug Powerline Alliance has developed a new standard for smart grid HAN communications called the HomePlug Green PHY specification. It is interoperable and coexistent with the widely deployed HomePlug AV technology and with the latest IEEE 1901 global Standard and is based on Broadband OFDM technology. ITU-T commissioned in 2010 a new project called G.hnem, to address the home networking aspects of energy management, built upon existing Low Frequency Narrowband OFDM technologies.

The Google.org's PowerMeter, until its demise in 2011, was able to use a smart meter for tracking electricity usage, as can eMeter' Energy Engage as in, for example, the PowerCentsDC(TM) demand response program. 

Advanced metering infrastructure

Advanced metering infrastructure (AMI) refers to systems that measure, collect, and analyze energy usage, and communicate with metering devices such as electricity meters, gas meters, heat meters, and water meters, either on request or on a schedule. These systems include hardware, software, communications, consumer energy displays and controllers, customer associated systems, meter data management software, and supplier business systems.

Government agencies and utilities are turning toward advanced metering infrastructure (AMI) systems as part of larger "smart grid" initiatives. AMI extends automatic meter reading (AMR) technology by providing two-way meter communications, allowing commands to be sent toward the home for multiple purposes, including time-based pricing information, demand-response actions, or remote service disconnects. Wireless technologies are critical elements of the neighborhood network, aggregating a mesh configuration of up to thousands of meters for back haul to the utility's IT headquarters.

The network between the measurement devices and business systems allows the collection and distribution of information to customers, suppliers, utility companies, and service providers. This enables these businesses to participate in demand response services. Consumers can use the information provided by the system to change their normal consumption patterns to take advantage of lower prices. Pricing can be used to curb the growth of peak demand consumption. AMI differs from traditional automatic meter reading (AMR) in that it enables two-way communications with the meter. Systems only capable of meter readings do not qualify as AMI systems.

Opposition and concerns

Some groups have expressed concerns regarding the cost, health, fire risk, security and privacy effects of smart meters and the remote controllable "kill switch" that is included with most of them. Many of these concerns regard wireless-only smart meters with no home energy monitoring or control or safety features. Metering-only solutions, while popular with utilities because they fit existing business models and have cheap up-front capital costs, often result in such "backlash". Often the entire smart grid and smart building concept is discredited in part by confusion about the difference between home control and home area network technology and AMI. The (now former) attorney general of Connecticut has stated that he does not believe smart meters provide any financial benefit to consumers, however, the cost of the installation of the new system is absorbed by those customers.

Security

Smart meters expose the power grid to cyberattacks that could lead to power outages, both by cutting off people's electricity and by overloading the grid. However many cyber security experts state that smart meters of UK and Germany have relatively high cybersecurity and that any such attack there would thus require extraordinarily high efforts or financial resources. The EU Cyber security Act took effect in June 2019, which includes Directive on Security Network and Information Systems establishing notification and security requirements for operators of essential services.

Through the Smartgrid Cybersecurity Committee, the U.S. Department of Energy published cybersecurity guidelines for grid operators in 2010 and updated them in 2014. The guidelines “...present an analytical framework that organizations can use to develop effective cybersecurity strategies...”

Implementing security protocols that protect these devices from malicious attacks has been problematic, due to their limited computational resources and long operational life.

The current version of IEC 62056 includes the possibility to encrypt, authenticate, or sign the meter data.

One proposed smart meter data verification method involves analyzing the network traffic in real-time to detect anomalies using an Intrusion Detection System (IDS). By identifying exploits as they are being leveraged by attackers, an IDS mitigates the suppliers' risks of energy theft by consumers and denial-of-service attacks by hackers. Energy utilities must choose between a centralized IDS, embedded IDS, or dedicated IDS depending on the individual needs of the utility. Researchers have found that for a typical advanced metering infrastructure, the centralized IDS architecture is superior in terms of cost efficiency and security gains.

In the United Kingdom, the Data Communication Company, which transports the commands from the supplier to the smart meter, performs an additional anomaly check on commands issued (and signed) by the energy supplier.

As Smart Meter devices are Intelligent Measurement Devices which periodically record the measured values and send the data encrypted to the Service Provider, therefore in Switzerland these devices need to be evaluated by an evaluation Laboratory, and need to be certified by METAS from 01.01.2020 according to Prüfmethodologie (Test Methodology for Execution of Data Security Evaluation of Swiss Smart Metering Components).

According to a report published by Brian Krebs, in 2009 a Puerto Rico electricity supplier asked the FBI to investigate large-scale thefts of electricity related to its smart meters. The FBI found that former employees of the power company and the company that made the meters were being paid by consumers to reprogram the devices to show incorrect results, as well as teaching people how to do it themselves.

Health

Most health concerns about the meters arise from the pulsed radiofrequency (RF) radiation emitted by wireless smart meters.

Members of the California State Assembly asked the California Council on Science and Technology (CCST) to study the issue of potential health impacts from smart meters, in particular whether current FCC standards are protective of public health. The CCST report in April 2011 found no health impacts, based both on lack of scientific evidence of harmful effects from radio frequency (RF) waves and that the RF exposure of people in their homes to smart meters is likely to be minuscule compared to RF exposure to cell phones and microwave ovens. Daniel Hirsch, retired director of the Program on Environmental and Nuclear Policy at UC Santa Cruz, criticized the CCST report on the grounds that it did not consider studies that suggest the potential for non-thermal health effects such as latent cancers from RF exposure. Hirsch also stated that the CCST report failed to correct errors in its comparison to cell phones and microwave ovens and that, when these errors are corrected, smart meters "may produce cumulative whole-body exposures far higher than that of cell phones or microwave ovens."

The Federal Communications Commission (FCC) has adopted recommended Permissible Exposure Limit (PEL) for all RF transmitters (including smart meters) operating at frequencies of 300 kHz to 100 GHz. These limits, based on field strength and power density, are below the levels of RF radiation that are hazardous to human health.

Other studies substantiate the finding of the California Council on Science and Technology (CCST). In 2011, the Electric Power Research Institute performed a study to gauge human exposure to smart meters as compared to the FCC PEL. The report found that most smart meters only transmit RF signals 1% of the time or less. At this rate, and at a distance of 1 foot from the meter, RF exposure would be at a rate of 0.14% of the FCC PEL.

An indirect potential for harm to health by smart meters is that they enable energy companies to disconnect consumers remotely, typically in response to difficulties with payment. This can cause health problems to vulnerable people in financial difficulty; in addition to denial of heat, lighting, and use of appliances, there are people who depend on power to use medical equipment essential for life. While there may be legal protections in place to protect the vulnerable, many people in the UK were disconnected in violation of the rules.

Safety

Issues surrounding smart meters causing fires have been reported, particularly involving the manufacturer Sensus. In 2012. PECO Energy Company replaced the Sensus meters it had deployed in the Philadelphia, US region after reports that a number of the units had overheated and caused fires. In July 2014, SaskPower, the province-run utility company of the Canadian province of Saskatchewan, halted its roll-out of Sensus meters after similar, isolated incidents were discovered. Shortly afterward, Portland General Electric announced that it would replace 70,000 smart meters that had been deployed in the state of Oregon after similar reports. The company noted that it had been aware of the issues since at least 2013, and they were limited to specific models it had installed between 2010 and 2012. On July 30, 2014, after a total of eight recent fire incidents involving the meters, SaskPower was ordered by the Government of Saskatchewan to immediately end its smart meter program, and remove the 105,000 smart meters it had installed.

Privacy concerns

One technical reason for privacy concerns is that these meters send detailed information about how much electricity is being used each time. More frequent reports provide more detailed information. Infrequent reports may be of little benefit for the provider, as it doesn't allow as good demand management in the response of changing needs for electricity. On the other hand, widespread reports would allow the utility company to infer behavioral patterns for the occupants of a house, such as when the members of the household are probably asleep or absent. Furthermore, the fine-grained information collected by smart meters raises growing concerns of privacy invasion due to personal behavior exposure (private activity, daily routine, etc.). Current trends are to increase the frequency of reports. A solution that benefits both provider and user privacy would be to adapt the interval dynamically. Another solution involves energy storage installed at the household used to reshape the energy consumption profile. In British Columbia the electric utility is government-owned and as such must comply with privacy laws that prevent the sale of data collected by smart meters; many parts of the world are serviced by private companies that are able to sell their data. In Australia debt collectors can make use of the data to know when people are at home. Used as evidence in a court case in Austin, Texas, police agencies secretly collected smart meter power usage data from thousands of residences to determine which used more power than "typical" to identify marijuana growing operations.

Smart meter power data usage patterns can reveal much more than how much power is being used. Research has demonstrated that smart meters sampling power levels at two-second intervals can reliably identify when different electrical devices are in use.

Ross Anderson wrote about privacy concerns "It is not necessary for my meter to tell the power company, let alone the government, how much I used in every half-hour period last month"; that meters can provide "targeting information for burglars"; that detailed energy usage history can help energy companies to sell users exploitative contracts; and that there may be "a temptation for policymakers to use smart metering data to target any needed power cuts."

Opt-out options

Reviews of smart meter programs, moratoriums, delays, and "opt-out" programs are some responses to the concerns of customers and government officials. In response to residents who did not want a smart meter, in June 2012 a utility in Hawaii changed its smart meter program to "opt out". The utility said that once the smart grid installation project is nearing completion, KIUC may convert the deferral policy to an opt-out policy or program and may charge a fee to those members to cover the costs of servicing the traditional meters. Any fee would require approval from the Hawaii Public Utilities Commission.

After receiving numerous complaints about health, hacking, and privacy concerns with the wireless digital devices, the Public Utility Commission of the US state of Maine voted to allow customers to opt-out of the meter change at the cost of $12 a month. In Connecticut, another US state to consider smart metering, regulators declined a request by the state's largest utility, Connecticut Light & Power, to install 1.2 million of the devices, arguing that the potential savings in electric bills do not justify the cost. CL&P already offers its customers time-based rates. The state's Attorney General George Jepsen was quoted as saying the proposal would cause customers to spend upwards of $500 million on meters and get few benefits in return, a claim that Connecticut Light & Power disputed.

Abuse of dynamic pricing

Smart meters allow dynamic pricing; it has been pointed out that, while this allows prices to be reduced at times of low demand, it can also be used to increase prices at peak times if all consumers have smart meters. Additionally smart meters allow energy suppliers to switch customers to expensive prepay tariffs instantly in case of difficulties paying. In the UK during a period of very high energy prices from 2022, companies were remotely switching smart meters from a credit tariff to an expensive prepay tariff which disconnects supplies unless credit has been purchased. While regulations do not permit this without appropriate precautions to help those in financial difficulties and to protect the vulnerable, the rules were often flouted. (Prepaid tariffs could also be levied without smart meters, but this required a dedicated prepay meter to be installed.) In 2022, 3.2 million people were left without power after running out of prepay credit.

Limited benefits

There are questions about whether electricity is or should be primarily a "when you need it" service where the inconvenience/cost-benefit ratio of time-shifting of loads is poor. In the Chicago area, Commonwealth Edison ran a test installing smart meters on 8,000 randomly selected households together with variable rates and rebates to encourage cutting back during peak usage. In Crain's Chicago Business article "Smart grid test underwhelms. In the pilot, few power down to save money.", it was reported that fewer than 9% exhibited any amount of peak usage reduction and that the overall amount of reduction was "statistically insignificant". This was from a report by the Electric Power Research Institute, a utility industry think tank who conducted the study and prepared the report. Susan Satter, senior assistant Illinois attorney general for public utilities said "It's devastating to their plan......The report shows zero statistically different result compared to business as usual." 

By 2016, the 7 million smart meters in Texas had not persuaded many people to check their energy data as the process was too complicated.

A report from a parliamentary group in the UK suggests people who have smart meters installed are expected to save an average of £11 annually on their energy bills, much less than originally hoped. The 2016 cost-benefit analysis was updated in 2019 and estimated a similar average saving.

The Australian Victorian Auditor-General found in 2015 that 'Victoria's electricity consumers will have paid an estimated $2.239 billion for metering services, including the rollout and connection of smart meters. In contrast, while a few benefits have accrued to consumers, benefits realisation is behind schedule and most benefits are yet to be realised'.

Erratic demand

Smart meters can allow real-time pricing, and in theory this could help smooth power consumption as consumers adjust their demand in response to price changes. However, modelling by researchers at the University of Bremen suggests that in certain circumstances, "power demand fluctuations are not dampened but amplified instead."

In the media

In 2013, Take Back Your Power, an independent Canadian documentary directed by Josh del Sol was released describing "dirty electricity" and the aforementioned issues with smart meters. The film explores the various contexts of the health, legal, and economic concerns. It features narration from the mayor of Peterborough, Ontario, Daryl Bennett, as well as American researcher De-Kun Li, journalist Blake Levitt, and Dr. Sam Milham. It won a Leo Award for best feature-length documentary and the Annual Humanitarian Award from Indie Fest the following year.

Criticism of smart meter roll-out in the UK

In a 2011 submission to the Public Accounts Committee, Anderson wrote that Ofgem was "making all the classic mistakes which have been known for years to lead to public-sector IT project failures" and that the "most critical part of the project—how smart meters will talk to domestic appliances to facilitate demand response—is essentially ignored."

Citizens Advice said in August 2018 that 80% of people with smart meters were happy with them. Still, it had 3,000 calls in 2017 about problems. These related to first-generation smart meters losing their functionality, aggressive sales practices, and still having to send smart meter readings.

Ross Anderson of the Foundation for Information Policy Research has criticised the UK's program on the grounds that it is unlikely to lower energy consumption, is rushed and expensive, and does not promote metering competition. Anderson writes, "the proposed architecture ensures continued dominance of metering by energy industry incumbents whose financial interests are in selling more energy rather than less," and urged ministers "to kill the project and instead promote competition in domestic energy metering, as the Germans do – and as the UK already has in industrial metering. Every consumer should have the right to appoint the meter operator of their choice."

The high number of SMETS1 meters installed has been criticized by Peter Earl, head of energy at the price comparison website comparethemarket.com. He said, "The Government expected there would only be a small number of the first-generation of smart meters before Smets II came in, but the reality is there are now at least five million and perhaps as many as 10 million Smets I meters."

UK smart meters in southern England and the Midlands use the mobile phone network to communicate, so they do not work correctly when phone coverage is weak. A solution has been proposed, but was not operational as of March 2017.

In March 2018 the National Audit Office (NAO), which watches over public spending, opened an investigation into the smart meter program, which had cost £11bn by then, paid for by electricity users through higher bills. The National Audit Office published the findings of its investigation in a report titled "Rolling out smart meters" published in November 2018. The report, amongst other findings, indicated that the number of smart meters installed in the UK would fall materially short of the Department for Business, Energy & Industrial Strategy (BEIS) original ambitions of all UK consumers having a smart meter installed by 2020. In September 2019, smart meter rollout in the UK was delayed for four years.

Ross Anderson and Alex Henney wrote that "Ed Miliband cooked the books" to make a case for smart meters appear economically viable. They say that the first three cost-benefit analyses of residential smart meters found that it would cost more than it would save, but "ministers kept on trying until they got a positive result... To achieve 'profitability' the previous government stretched the assumptions shamelessly".

A counter-fraud officer at Ofgem with oversight of the roll-out of the smart meter program who raised concerns with his manager about many millions of pounds being misspent was threatened with imprisonment under section 105 of the Utilities Act 2000, a provision intended to protect national security. The Employment Appeal Tribunal found that the law was in contravention of the European Convention on Human Rights.

Palindrome

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Palindrome

 

The 4th-century Greek palindrome: ΝΙΨΟΝ ΑΝΟΜΗΜΑΤΑ ΜΗ ΜΟΝΑΝ ΟΨΙΝ (Wash your sins, not only your face), at the Hagia Sophia in Constantinople.

A palindrome is a word, number, phrase, or other sequence of symbols that reads the same backwards as forwards, such as madam or racecar, the date and time 12/21/33 12:21, and the sentence: "A man, a plan, a canal – Panama". The 19-letter Finnish word saippuakivikauppias (a soapstone vendor), is the longest single-word palindrome in everyday use, while the 12-letter term tattarrattat (from James Joyce in Ulysses) is the longest in English.

The word palindrome was introduced by English poet and writer Henry Peacham in 1638. The concept of a palindrome can be dated to the 3rd-century BCE, although no examples survive; the first physical examples can be dated to the 1st-century CE with the Latin acrostic word square, the Sator Square (contains both word and sentence palindromes), and the 4th-century Greek Byzantine sentence palindrome nipson anomemata me monan opsin.

Palindromes are also found in music (the table canon and crab canon) and biological structures (most genomes include palindromic gene sequences). In automata theory, the set of all palindromes over an alphabet is a context-free language, but it is not regular.

Etymology

The word palindrome was introduced by English poet and writer Henry Peacham in 1638. It is derived from the Greek roots πάλιν 'again' and δρóμος 'way, direction'; a different word is used in Greek, καρκινικός 'carcinic' (lit. crab-like) to refer to letter-by-letter reversible writing.

Historical development

A Sator square (in SATOR-form), on a wall in the medieval fortress town of Oppède-le-Vieux, France

The ancient Greek poet Sotades (3rd-century BC) invented a form of Ionic meter called Sotadic or Sotadean verse, which is sometimes said to have been palindromic, since it is sometimes possible to make a sotadean line by reversing a dactylic hexameter.

A 1st-century Latin palindrome was found as a graffito at Pompeii. This palindrome, known as the Sator Square, consists of a sentence written in Latin: sator arepo tenet opera rotas 'The sower Arepo holds with effort the wheels'. It is also an acrostic where the first letters of each word form the first word, the second letters form the second word, and so forth. Hence, it can be arranged into a word square that reads in four different ways: horizontally or vertically from either top left to bottom right or bottom right to top left. Other palindromes found at Pompeii include "Roma-Olina-Milo-Amor", which is also written as an acrostic square. Indeed, composing palindromes was "a pastime of Roman landed gentry".

Nipson anomēmata mē monan opsin palindrome, on a font at St Martin, Ludgate

Byzantine baptismal fonts were often inscribed with the 4th-century Greek palindrome, ΝΙΨΟΝ ΑΝΟΜΗΜΑΤΑ (or ΑΝΟΜΗΜΑ) ΜΗ ΜΟΝΑΝ ΟΨΙΝ ("Nipson anomēmata mē monan opsin") 'Wash [your] sin(s), not only [your] face', attributed to Gregory of Nazianzus; most notably in the basilica of Hagia Sophia in Constantinople. The inscription is found on fonts in many churches in Western Europe: Orléans (St. Menin's Abbey); Dulwich College; Nottingham (St. Mary's); Worlingworth; Harlow; Knapton; London (St Martin, Ludgate); and Hadleigh (Suffolk).

An 11th-century palindrome with the same square property is the Hebrew palindrome, פרשנו רעבתן שבדבש נתבער ונשרף perashnu: ra`avtan shebad'vash nitba`er venisraf 'We explained the glutton who is in the honey was burned and incinerated', credited to Abraham ibn Ezra in 1924, and referring to the halachic question as to whether a fly landing in honey makes the honey treif (non-kosher).

The palindromic Latin riddle "In girum imus nocte et consumimur igni" 'we go in a circle at night and are consumed by fire' describes the behavior of moths. It is likely that this palindrome is from medieval rather than ancient times. The second word, borrowed from Greek, should properly be spelled gyrum.

In English, there are many palindrome words such as eye, madam, and deified, but English writers generally cited Latin and Greek palindromic sentences in the early 19th century; though John Taylor had coined one in 1614: "Lewd did I live, & evil I did dwel" (with the ampersand being something of a "fudge"). This is generally considered the first English-language palindrome sentence and was long-reputed, notably by the grammarian James "Hermes" Harris, to be the only one, despite many efforts to find others.^] (Taylor had also composed two other, "rather indifferent", palindromic lines of poetry: "Deer Madam, Reed", "Deem if I meed".) Then in 1848, a certain "J.T.R." coined "Able was I ere I saw Elba", which became famous after it was (implausibly) attributed to Napoleon (alluding to his exile on Elba). Other well-known English palindromes are: "A man, a plan, a canal – Panama" (1948), "Madam, I'm Adam" (1861), and "Never odd or even".

Types

Characters, words, or lines

The most familiar palindromes in English are character-unit palindromes, where the characters read the same backward as forward. Examples are civic, radar, level, rotor, kayak, madam, and refer. The longest common ones are rotator, deified, racecar and reviver; longer examples such as redivider, kinnikinnik and tattarrattat are orders of magnitude rarer.

There are also word-unit palindromes in which the unit of reversal is the word ("Is it crazy how saying sentences backwards creates backwards sentences saying how crazy it is?"). Word-unit palindromes were made popular in the recreational linguistics community by J. A. Lindon in the 1960s. Occasional examples in English were created in the 19th century. Several in French and Latin date to the Middle Ages.

There are also line-unit palindromes, most often poems. These possess an initial set of lines which, precisely halfway through, is repeated in reverse order, without alteration to word order within each line, and in a way that the second half continues the "story" related in the first half in a way that makes sense, this last being key.

Sentences and phrases

Ambigram of the palindrome "Dogma I am God"

Palindromes often consist of a sentence or phrase, e.g., "Mr. Owl ate my metal worm", "Do geese see God?", or "Was it a car or a cat I saw?". Punctuation, capitalization, and spaces are usually ignored. Some, such as "Rats live on no evil star", "Live on time, emit no evil", and "Step on no pets", include the spaces.

Names

Some names are palindromes, such as the given names Hannah, Ava, Aviva, Anna, Eve, Bob and Otto, or the surnames Harrah, Renner, Salas, and Nenonen. Lon Nol (1913–1985) was Prime Minister of Cambodia. Nisio Isin is a Japanese novelist and manga writer, whose pseudonym (西尾 維新, Nishio Ishin) is a palindrome when romanized using the Kunrei-shiki or the Nihon-shiki systems, and is often written as NisiOisiN to emphasize this. Some people have changed their name in order to make it palindromic (including as the actor Robert Trebor and rock-vocalist Ola Salo), while others were given a palindromic name at birth (such as the philologist Revilo P. Oliver, the flamenco dancer Sara Baras, the runner Anuța Cătună, the sportswriter Mark Kram and the creator of the Eden Project Tim Smit).

There are also palindromic names in fictional media. "Stanley Yelnats" is the name of the main character in Holes, a 1998 novel and 2003 film. Five of the fictional Pokémon species have palindromic names in English (Eevee, Girafarig, Farigiraf, Ho-Oh, and Alomomola), as does the region Alola.

The 1970s pop band ABBA is a palindrome using the starting letter of the first name of each of the four band members.

Numbers

Main article: Palindromic number

Main article: Periodic continued fraction

The digits of a palindromic number are the same read backwards as forwards, for example, 91019; decimal representation is usually assumed. In recreational mathematics, palindromic numbers with special properties are sought. For example, 191 and 313 are palindromic primes.

Whether Lychrel numbers exist is an unsolved problem in mathematics about whether all numbers become palindromes when they are continuously reversed and added. For example, 56 is not a Lychrel number as 56 + 65 = 121, and 121 is a palindrome. The number 59 becomes a palindrome after three iterations: 59 + 95 = 154; 154 + 451 = 605; 605 + 506 = 1111, so 59 is not a Lychrel number either. Numbers such as 196 are thought to never become palindromes when this reversal process is carried out and are therefore suspected of being Lychrel numbers. If a number is not a Lychrel number, it is called a "delayed palindrome" (56 has a delay of 1 and 59 has a delay of 3). In January 2017 the number 1,999,291,987,030,606,810 was published in OEIS as A281509, and described as "The Largest Known Most Delayed Palindrome", with a delay of 261. Several smaller 261-delay palindromes were published separately as A281508.

Every positive integer can be written as the sum of three palindromic numbers in every number system with base 5 or greater.

Dates

A day or timestamp is a palindrome when its digits are the same when reversed. Only the digits are considered in this determination and the component separators (hyphens, slashes, and dots) are ignored. Short digits may be used as in 11/11/11 11:11 or long digits as in 2 February 2020.

A notable palindrome day is this century's 2 February 2020 because this date is a palindrome regardless of the date format by country (yyyy-mm-dd, dd-mm-yyyy, or mm-dd-yyyy) used in various countries. For this reason, this date has also been termed as a "Universal Palindrome Day". Other universal palindrome days include, almost a millennium previously, 11/11/1111, the future 12/12/2121, and in a millennium 03/03/3030.

In speech

A phonetic palindrome is a portion of speech that is identical or roughly identical when reversed. It can arise in context where language is played with, for example in slang dialects like verlan. In the French language, there is the phrase une Slave valse nue ("a Slavic woman waltzes naked"), phonemically /yn slav vals ny/. John Oswald discussed his experience of phonetic palindromes while working on audio tape versions of the cut-up technique using recorded readings by William S. Burroughs. A list of phonetic palindromes discussed by word puzzle columnist O.V. Michaelsen (Ove Ofteness) include "crew work"/"work crew", "dry yard", "easy", "Funny enough", "Let Bob tell", "new moon", "selfless", "Sorry, Ross", "Talk, Scott", "to boot", "top spot" (also an orthographic palindrome), "Y'all lie", "You're caught. Talk, Roy", and "You're damn mad, Roy".

Longest palindromes

The longest single-word palindrome in the Oxford English Dictionary is the 12-letter onomatopoeic word tattarrattat, coined by James Joyce in Ulysses (1922) for a knock on the door. The Guinness Book of Records gives the title to the 11-letter detartrated, the preterite and past participle of detartrate, a chemical term meaning to remove tartrates. The 9-letter word Rotavator, a trademarked name for an agricultural machine, is listed in dictionaries as being the longest single-word palindrome. The 9-letter term redivider is used by some writers, but appears to be an invented or derived term; only redivide and redivision appear in the Shorter Oxford English Dictionary; the 9-letter word Malayalam, a language of southern India, is also of equal length.

According to Guinness World Records, the Finnish 19-letter word saippuakivikauppias (a soapstone vendor), is the world's longest palindromic word in everyday use.

English palindrome sentences of notable length include mathematician Peter Hilton's "Doc, note: I dissent. A fast never prevents a fatness. I diet on cod", and Scottish poet Alastair Reid's "T. Eliot, top bard, notes putrid tang emanating, is sad; I'd assign it a name: gnat dirt upset on drab pot toilet."

In English, two palindromic novels have been published: Satire: Veritas by David Stephens (1980, 58,795 letters), and Dr Awkward & Olson in Oslo by Lawrence Levine (1986, 31,954 words). Another palindromic English work is a 224-word long poem, "Dammit I'm Mad", written by Demetri Martin. "Weird Al" Yankovic's song "Bob" is composed entirely of palindromes.

Other occurrences

Classical music

Centre part of palindrome in Alban Berg's opera Lulu

Joseph Haydn's Symphony No. 47 in G is nicknamed "the Palindrome". In the third movement, a minuet and trio, the second half of the minuet is the same as the first but backwards, the second half of the ensuing trio similarly reflects the first half, and then the minuet is repeated.

The interlude from Alban Berg's opera Lulu is a palindrome, as are sections and pieces, in arch form, by many other composers, including James Tenney, and most famously Béla Bartók. George Crumb also used musical palindrome to text paint the Federico García Lorca poem "¿Por qué nací?", the first movement of three in his fourth book of Madrigals. Igor Stravinsky's final composition, The Owl and the Pussy Cat, is a palindrome.

The first movement from Constant Lambert's ballet Horoscope (1938) is entitled "Palindromic Prelude". Lambert claimed that the theme was dictated to him by the ghost of Bernard van Dieren, who had died in 1936.

British composer Robert Simpson also composed music in the palindrome or based on palindromic themes; the slow movement of his Symphony No. 2 is a palindrome, as is the slow movement of his String Quartet No. 1. His hour-long String Quartet No. 9 consists of thirty-two variations and a fugue on a palindromic theme of Haydn (from the minuet of his Symphony No. 47). All of Simpson's thirty-two variations are themselves palindromic.

Hin und Zurück ("There and Back": 1927) is an operatic 'sketch' (Op. 45a) in one scene by Paul Hindemith, with a German libretto by Marcellus Schiffer. It is essentially a dramatic palindrome. Through the first half, a tragedy unfolds between two lovers, involving jealousy, murder and suicide. Then, in the reversing second half, this is replayed with the lines sung in reverse order to produce a happy ending.

The music of Anton Webern is often palindromic. Webern, who had studied the music of the Renaissance composer Heinrich Isaac, was extremely interested in symmetries in music, be they horizontal or vertical. An example of horizontal or linear symmetry in Webern's music is the first phrase in the second movement of the symphony, Op. 21. A striking example of vertical symmetry is the second movement of the Piano Variations, Op. 27, in which Webern arranges every pitch of this dodecaphonic work around the central pitch axis of A4. From this, each downward reaching interval is replicated exactly in the opposite direction. For example, a G♯3—13 half-steps down from A4 is replicated as a B♭5—13 half-steps above.

Just as the letters of a verbal palindrome are not reversed, so are the elements of a musical palindrome usually presented in the same form in both halves. Although these elements are usually single notes, palindromes may be made using more complex elements. For example, Karlheinz Stockhausen's composition Mixtur, originally written in 1964, consists of twenty sections, called "moments", which may be permuted in several different ways, including retrograde presentation, and two versions may be made in a single program. When the composer revised the work in 2003, he prescribed such a palindromic performance, with the twenty moments first played in a "forwards" version, and then "backwards". Each moment, however, is a complex musical unit, and is played in the same direction in each half of the program. By contrast, Karel Goeyvaerts's 1953 electronic composition, Nummer 5 (met zuivere tonen) is an exact palindrome: not only does each event in the second half of the piece occur according to an axis of symmetry at the centre of the work, but each event itself is reversed, so that the note attacks in the first half become note decays in the second, and vice versa. It is a perfect example of Goeyvaerts's aesthetics, the perfect example of the imperfection of perfection.

In classical music, a crab canon is a canon in which one line of the melody is reversed in time and pitch from the other. A large-scale musical palindrome covering more than one movement is called "chiastic", referring to the cross-shaped Greek letter "χ" (pronounced /ˈkaɪ/.) This is usually a form of reference to the crucifixion; for example, the Crucifixus movement of Bach's Mass in B minor. The purpose of such palindromic balancing is to focus the listener on the central movement, much as one would focus on the centre of the cross in the crucifixion. Other examples are found in Bach's cantata BWV 4, Christ lag in Todes Banden, Handel's Messiah and Fauré's Requiem.

A table canon is a rectangular piece of sheet music intended to be played by two musicians facing each other across a table with the music between them, with one musician viewing the music upside down compared to the other. The result is somewhat like two speakers simultaneously reading the Sator Square from opposite sides, except that it is typically in two-part polyphony rather than in unison.

Biological structures

Main article: Palindromic sequence

 

Palindrome of DNA structure A: Palindrome, B: Loop, C: Stem

Palindromic motifs are found in most genomes or sets of genetic instructions, palindromic motifs are found. The meaning of palindrome in the context of genetics is slightly different, from the definition used for words and sentences. Since the DNA is formed by two paired strands of nucleotides, and the nucleotides always pair in the same way (Adenine (A) with Thymine (T), Cytosine (C) with Guanine (G)), a (single-stranded) sequence of DNA is said to be a palindrome if it is equal to its complementary sequence read backward. For example, the sequence ACCTAGGT is palindromic because its complement is TGGATCCA, which is equal to the original sequence in reverse complement.

A palindromic DNA sequence may form a hairpin. Palindromic motifs are made by the order of the nucleotides that specify the complex chemicals (proteins) that, as a result of those genetic instructions, the cell is to produce. They have been specially researched in bacterial chromosomes and in the so-called Bacterial Interspersed Mosaic Elements (BIMEs) scattered over them. Recently a research genome sequencing project discovered that many of the bases on the Y-chromosome are arranged as palindromes. A palindrome structure allows the Y-chromosome to repair itself by bending over at the middle if one side is damaged.

It is believed that palindromes are also found in proteins, but their role in the protein function is not clearly known. It has recently been suggested that the prevalence existence of palindromes in peptides might be related to the prevalence of low-complexity regions in proteins, as palindromes frequently are associated with low-complexity sequences. Their prevalence might also be related to an alpha helical formation propensity of these sequences, or in formation of proteins/protein complexes.

Computation theory

In automata theory, a set of all palindromes in a given alphabet is a typical example of a language that is context-free, but not regular. This means that it is impossible for a computer with a finite amount of memory to reliably test for palindromes. (For practical purposes with modern computers, this limitation would apply only to impractically long letter sequences.)

In addition, the set of palindromes may not be reliably tested by a deterministic pushdown automaton which also means that they are not LR(k)-parsable or LL(k)-parsable. When reading a palindrome from left to right, it is, in essence, impossible to locate the "middle" until the entire word has been read completely.

It is possible to find the longest palindromic substring of a given input string in linear time.

The palindromic density of an infinite word w over an alphabet A is defined to be zero if only finitely many prefixes are palindromes; otherwise, letting the palindromic prefixes be of lengths n_k for k=1,2,... we define the density to be

${\displaystyle d_P(w)={\left(\underset{k\to \mathrm{\infty }}{lim sup}\frac{n_{k+1}}{n_k}\right)}^{-1}.}$

Among aperiodic words, the largest possible palindromic density is achieved by the Fibonacci word, which has density 1/φ, where φ is the Golden ratio.

A palstar is a concatenation of palindromic strings, excluding the trivial one-letter palindromes – otherwise all strings would be palstars.

Solid-state battery

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Solid-state_battery 

A solid-state battery deploys solid-state technology using solid electrodes and a solid electrolyte, instead of the liquid or polymer gel electrolytes found in lithium-ion or lithium polymer batteries.

While solid electrolytes were first discovered in the 19th century, several drawbacks have prevented widespread application. Developments in the late 20th and early 21st century have caused renewed interest in solid-state battery technologies, especially in the context of electric vehicles, starting in the 2010s.

Solid-state technology batteries can provide potential solutions for many problems of liquid Li-ion batteries, such as flammability, limited voltage, unstable solid-electrolyte interphase formation, poor cycling performance and strength.

Materials proposed for use as solid electrolytes in solid-state batteries include ceramics (e.g., oxides, sulfides, phosphates), and solid polymers. Solid-state batteries have found use in pacemakers, RFID and wearable devices. Solid-state technology used in these batteries is potentially safer, with higher energy densities, but at a much higher cost. Challenges to widespread adoption include energy and power density, durability, material costs, sensitivity and stability.

History

Between 1831 and 1834, Michael Faraday discovered the solid electrolytes silver sulfide and lead(II) fluoride, which laid the foundation for solid-state ionics.

By the late 1950s, several silver-conducting electrochemical systems employed solid electrolytes, but such systems possessed undesirable qualities, including low energy density and cell voltages, and high internal resistance. In 1967, the discovery of fast ionic conduction β - alumina for a broad class of ions (Li+, Na+, K+, Ag+, and Rb+) kick-started excitement for and the development of new solid-state electrochemical devices with increased energy density. Most immediately, molten sodium / β - alumina / sulfur cells were developed at Ford Motor Company in the US, and NGK in Japan. This excitement for solid-state electrolytes manifested in the discovery of new systems in both organics, i.e. poly(ethylene) oxide (PEO), and inorganics such as NASICON. However, many of these systems commonly required operation at elevated temperatures, and / or were expensive to produce, enabling only limited commercial deployment. A new class of solid-state electrolyte developed by the Oak Ridge National Laboratory, Lithium phosphorus oxynitride (LiPON), emerged in the 1990s. While LiPON was successfully used to make thin film lithium-ion batteries, such applications were limited due to the cost associated with deposition of the thin-film electrolyte, along with the small capacities that could be accessed using the thin film format.

In 2011, the landmark work of Kamaya et al. demonstrated the first solid-electrolyte, Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP), capable of achieving a bulk ionic conductivity in excess of liquid electrolyte counterparts at room temperature. With this, bulk solid-ion conductors could finally compete technologically with Li-ion counterparts, leading to the modern era of solid-state research.

2000's Commercial Research & Development

As technology advanced into the new millennium, researchers and companies in the automotive and transportation industries experienced revitalized interest in solid-state battery technologies. In 2011, Bolloré launched a fleet of their BlueCar model cars, first in cooperation with carsharing service Autolib, and later released to retail customers. The car was meant to showcase the company's diversity of electric-powered cells in the application, and featured a 30 kWh lithium metal polymer (LMP) battery with a polymeric electrolyte, created by dissolving lithium salt in a co-polymer (polyoxyethylene).

In 2012, Toyota soon followed suit and began conducting experimental research into solid-state batteries for applications in the automotive industry in order to remain competitive in the EV market. At the same time, Volkswagen began partnering with small technology companies specializing in the technology.

A series of technological breakthroughs ensued. In 2013, researchers at the University of Colorado Boulder announced the development of a solid-state lithium battery, with a solid composite cathode based on an iron-sulfur chemistry, that promised higher energy capacity compared to already-existing SSBs.

In 2017, John Goodenough, the co-inventor of Li-ion batteries, unveiled a solid-state glass battery, using a glass electrolyte and an alkali-metal anode consisting of lithium, sodium or potassium. Later that year, Toyota announced the deepening of its decades-long partnership with Panasonic, including a collaboration on solid-state batteries. Due to its early intensive research and coordinated collaborations with other industry leaders, Toyota holds the most SSB-related patents. However, other car makers independently developing solid-state battery technologies quickly joined a growing list that includes BMW, Honda, Hyundai Motor Company and Nissan. Other automotive-related companies, such as Spark plug maker NGK, have retrofitted their business expertise and models to cater to evolving demand for ceramic-based solid state batteries, in the face of perceived obsolescence of the conventional fossil-fuel paradigm.

Major developments continued to unfold into 2018, when Solid Power, spun off from the University of Colorado Boulder research team, received $20 million in funding from Samsung and Hyundai to establish a small manufacturing line that could produce copies of its all-solid-state, rechargeable lithium-metal battery prototype, with a predicted 10 megawatt hours of capacity per year.

QuantumScape, another solid-state battery startup that spun out of a collegiate research group (in this case, Stanford University) drew attention that same year, when Volkswagen announced a $100 million investment into the team's research, becoming the largest stakeholder, joined by investor Bill Gates. With the goal to establish a joint production project for mass production of solid-state batteries, Volkswagen endowed QuantumScape with an additional $200 million in June 2020, and QuantumScape IPO'd on the NYSE on November 29, 2020, as part of a merger with Kensington Capital Acquisition, to raise additional equity capital for the project. QuantumScape has "scheduled mass production to begin in the second half of 2024".

Qing Tao started the first Chinese production line of solid-state batteries in 2018 as well, with the initial intention of supplying SSBs for “special equipment and high-end digital products”; however, the company has spoken with several car manufacturers with the intent to potentially expand into the automotive space.

In July 2021, Murata Manufacturing announced that it will begin mass production of all-solid-state batteries in the coming months, aiming to supply them to manufacturers of earphones and other wearables. The battery capacity is up to 25mAh at 3.8V, making it suitable for small mobile devices such as earbuds, but not for electric vehicles. Lithium-Ion cells used in electric vehicles typically offer 2,000 to 5,000 mAh at similar voltage: an EV would need at least 100 times as many of the Murata cells to provide equivalent power.

Ford Motor Company and BMW funded the startup Solid Power with $130 million, and as of 2022 the company has raised a total of $540 million.

In September 2021, Toyota announced their plan to use a solid-state battery in some future car models, starting with hybrid models in 2025, due to the cost and lower power requirements.

In early 2022, Swiss Clean Battery (SCB) announced it's plans to open the world's first factory for sustainable solid-state batteries in Frauenfeld by 2024 with an initial production of 1.2 GWH which is planned to be scaled to 7.6 GWh.

In January 2022, ProLogium Technology signed a technical cooperation agreement with Mercedes-Benz, a subsidiary of the Daimler Group. The money invested by Mercedes-Benz will be used for solid-state battery development and production preparations.

In February 2022, Alpine 4 Holdings subsidiaries Elecjet and Vayu Aerospace successfully installed Solid State Batteries in their drones leading up to a sale to a Government Contractor later in the year. In July 2022, Svolt announced the production of a 20 Ah electric battery with an energy density of 350-400 Wh/kg.

Materials

See also: Solid-state electrolyte

Solid-state electrolytes (SSEs) candidate materials include ceramics such as lithium orthosilicate, glass, sulfides and RbAg₄I₅. Mainstream oxide solid electrolytes include Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP), Li_1.4Al_0.4Ti_1.6(PO₄)₃ (LATP), perovskite-type Li_3xLa_2/3-xTiO₃ (LLTO), and garnet-type Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZO) with metallic Li. The thermal stability versus Li of the four SSEs was in order of LAGP < LATP < LLTO < LLZO. Chloride superionic conductors have been proposed as another promising solid electrolyte. They are ionic conductive as well as deformable sulfides, but at the same time not troubled by the poor oxidation stability of sulfides. Other than that, their cost is considered lower than oxide and sulfide SSEs. The present chloride solid electrolyte systems can be divided into two types: Li₃MCl₆ and Li₂M_2/3Cl₄. M Elements include Y, Tb-Lu, Sc, and In. The cathodes are lithium based. Variants include LiCoO₂, LiNi_1/3Co_1/3Mn_1/3O₂, LiMn₂O₄, and LiNi_0.8Co_0.15Al_0.05O₂. The anodes vary more and are affected by the type of electrolyte. Examples include In, Si, Ge_xSi_1−x, SnO–B₂O₃, SnS –P₂S₅, Li₂FeS₂, FeS, NiP₂, and Li₂SiS₃.

One promising cathode material is Li-S, which (as part of a solid lithium anode/Li₂S cell) has a theoretical specific capacity of 1670 mAh g⁻¹, "ten times larger than the effective value of LiCoO₂". Sulfur makes an unsuitable cathode in liquid electrolyte applications because it is soluble in most liquid electrolytes, dramatically decreasing the battery's lifetime. Sulfur is studied in solid state applications. Recently, a ceramic textile was developed that showed promise in a Li-S solid state battery. This textile facilitated ion transmission while also handling sulfur loading, although it did not reach the projected energy density. The result "with a 500-μm-thick electrolyte support and 63% utilization of electrolyte area" was "71 Wh/kg." while the projected energy density was 500 Wh/kg.

Li-O₂ also have high theoretical capacity. The main issue with these devices is that the anode must be sealed from ambient atmosphere, while the cathode must be in contact with it.

A Li/LiFePO₄ battery shows promise as a solid state application for electric vehicles. A 2010 study presented this material as a safe alternative to rechargeable batteries for EV's that "surpass the USABC-DOE targets".

A cell with a pure silicon μSi||SSE||NCM811 anode was assembled by Darren H.S Tan et al. using μSi anode(purity of 99.9 wt %), solid state electrolyte (SSE) and lithium nickel cobalt manganese oxide (NCM811) cathode. This kind of solid state battery demonstrated a high current density up to 5 mA cm⁻², a wide range of working temperature (-20 °C and 80 °C), and areal capacity (for the anode) of up to 11 mAh cm⁻² (2890 mAh/g). At the same time, after 500 cycles under 5 mA cm⁻², the batteries still provide 80% of capacity retention, which is the best performance of μSi all solid-state battery reported so far.

Chloride solid electrolytes also show promise over conventional oxide solid electrolytes owing to chloride solid electrolytes having theoretically higher ionic conductivity and better formability. In addition chloride solid electrolyte’s exceptionally high oxidation stability and high ductility add to its performance. In particular a lithium mixed-metal chloride family of solid electrolytes, Li₂In_xSc_0.666-xCl₄ developed by Zhou et tal., show high ionic conductivity (2.0 mS cm⁻¹) over a wide range of composition. This is owing to the chloride solid electrolyte being able to be used in conjunction with bare cathode active materials as opposed to coated cathode active materials and its low electronic conductivity. Alternative cheaper chloride solid electrolyte compositions with lower, but still impressive, ionic conductivity can be found with an Li₂ZrCl₆ solid electrolyte. This particular chloride solid electrolyte maintains a high room temperature ionic conductivity (0.81 mS cm⁻¹), deformability, and has a high humidity tolerance.

Uses

Solid-state batteries are potentially useful in pacemakers, RFIDs, wearable devices, and electric vehicles.

Electric vehicles

See also: Electric vehicle

Hybrid and plug-in electric cars use a variety of battery technologies, including Li-ion, nickel–metal hydride (NiMH), lead–acid, and electric double-layer capacitor (or ultracapacitor), with Li-ion dominating the market. In August 2020, Toyota started road testing of their prototype vehicle, LQ Concept, equipped with a solid-state battery. In September 2021, Toyota unveiled its strategy on battery development and supply, in which solid-state battery is to be adopted first in their hybrid electric vehicles to utilize its characteristics. And, Honda has set their plan schedule to start operation of demonstration line for the production of all-solid-state batteries in Spring 2024.

Wearables

See also: Wearable technology

The characteristics of high energy density and keeping high performance even in harsh environments are expected in realization of new wearable devices that are smaller and more reliable than ever.

Equipment in space

In March 2021, industrial manufacturer Hitachi Zosen Corporation announced a solid-state battery they claimed has one of the highest capacities in the industry and has a wider operating temperature range, potentially suitable for harsh environments like space. A test mission was launched in February 2022, and in August, Japan Aerospace Exploration Agency (JAXA) announced the solid-state batteries had properly operated in space, powering camera equipment in the Japanese Experiment Module Kibō on the International Space Station (ISS).

Drones

Being lighter weight and more powerful than traditional lithium ion batteries it is reasonable that drones would benefit from Solid State batteries. Vayu Aerospace, a drone manufacturer and designer, noted an increased flight time after they incorporated them into their G1 long flight drone.

Challenges

Cost

Thin-film solid-state batteries are expensive to make and employ manufacturing processes thought to be difficult to scale, requiring expensive vacuum deposition equipment. As a result, costs for thin-film solid-state batteries become prohibitive in consumer-based applications. It was estimated in 2012 that, based on then-current technology, a 20 Ah solid-state battery cell would cost US$100,000, and a high-range electric car would require between 800 and 1,000 of such cells. Likewise, cost has impeded the adoption of thin film solid-state batteries in other areas, such as smartphones.

Temperature and pressure sensitivity

Low temperature operations may be challenging. Solid-state batteries historically have had poor performance.

Solid-state batteries with ceramic electrolytes require high pressure to maintain contact with the electrodes. Solid-state batteries with ceramic separators may break from mechanical stress.

In November 2022, Japanese research group, consisting of Kyoto University, Tottori University and Sumitomo Chemical, announced that they have managed to operate solid-state batteries stably without applying pressure with 230Wh/kg capacity by using copolymerized new materials for electrolyte.

Interfacial resistance

High interfacial resistance between a cathode and solid electrolyte has been a long-standing problem for all-solid-state batteries.

Interfacial instability

The interfacial instability of the electrode-electrolyte has always been a serious problem in solid state batteries. After solid state electrolyte contacts with electrode, the chemical and/or electrochemical side reactions at the interface usually produce a passivated interface, which impedes the diffusion of Li⁺ across the electrode-SSE interface. Upon high-voltage cycling, some SSEs may undergo oxidative degradation.

Dendrites

Lithium metal dendrite from the anode piercing through the separator and growing towards the cathode.

Solid lithium (Li) metal anodes in solid-state batteries are replacement candidates in lithium-ion batteries for higher energy densities, safety, and faster recharging times. Such anodes tend to suffer from the formation and the growth of Li dendrites, non-uniform metal growths which penetrate the electrolyte lead to electrical short circuits. This shorting leads to energy discharge, overheating, and sometimes fires or explosions due to thermal runaway. Li dendrites reduce coulombic efficiency.

The exact mechanisms of dendrite growth remain a subject of research. Studies of metal dendrite growth in solid electrolytes began with research of molten sodium / sodium - β - alumina / sulfur cells at elevated temperature. In these systems, dendrites sometimes grow as a result of micro-crack extension due to the presence of plating-induced pressure at the sodium / solid electrolyte interface. However, dendrite growth may also occur due to chemical degradation of the solid electrolyte.

In Li-ion solid electrolytes stable to Li metal, dendrites propagate primarily due to pressure build up at the electrode / solid electrolyte interface, leading to crack extension. Meanwhile, for solid electrolytes which are chemically unstable against their respective metal, interphase growth and eventual cracking often prevents dendrites from forming.

Dendrite growth in solid-state Li-ion cells can be mitigated by operating the cells at elevated temperature, or by using residual stresses to fracture toughen electrolytes, thereby deflecting dendrites and delaying dendrite induced short-circuiting. Aluminum-containing electronic rectifying interphases between the solid-state electrolyte and the lithium metal anode have also been shown to be effective in preventing dendrite growth.

Mechanical failure

A common failure mechanism in solid-state batteries is mechanical failure through volume changes in the anode and cathode during charge and discharge due to the addition and removal of Li-ions from the host structures.

Cathode

Cathodes will typically consist of active cathode particles mixed with SSE particles to assist with ion conduction. As the battery charges/discharges, the cathode particles change in volume typically on the order of a few percent. This volume change leads to the formation of interparticle voids which worsens contact between the cathode and SSE particles, resulting in a significant loss of capacity due to the restriction in ion transport.

One proposed solution to this issue is to take advantage of the anisotropy of volume change in the cathode particles. As many cathode materials experience volume changes only along certain crystallographic directions, if the secondary cathode particles are grown along a crystallographic direction which does not expand greatly with charge/discharge, then the change in volume of the particles can be minimized. Another proposed solution is to mix different cathode materials which have opposite expansion trends in the proper ratio such that the net volume change of the cathode is zero. For instance, LiCoO₂ (LCO) and LiNi_0.9Mn_0.05Co_0.05O₂ (NMC) are two well-known cathode materials for Li-ion batteries. LCO has been shown to undergo volume expansion when discharged while NMC has been shown to undergo volume contraction when discharged. Thus, a composite cathode of LCO and NMC at the correct ratio could undergo minimal volume change under discharge as the contraction of NMC is compensated by the expansion of LCO.

Anode

Ideally a solid-state battery would use a pure lithium metal anode due to its high energy capacity. However, lithium undergoes a large increase of volume during charge at around 5 µm per 1 mAh/cm² of plated Li. For electrolytes with a porous microstructure, this expansion leads to an increase in pressure which can lead to creep of Li metal through the electrolyte pores and short of the cell. Lithium metal has a relatively low melting point of 453K and a low activation energy for self-diffusion of 50 kJ/mol, indicating its high propensity to significantly creep at room temperature. It has been shown that at room temperature lithium undergoes power-law creep where the temperature is high enough relative to the melting point that dislocations in the metal can climb out of their glide plane to avoid obstacles. The creep stress under power-law creep is given by:

${\displaystyle {\sigma }_{creep}={\left(\frac{\dot{\epsilon }}{A_c}\right)}^{1/m}\exp \left(\frac{Q_c}{mRT}\right)}$

Where ${\displaystyle R}$ is the gas constant, ${\displaystyle T}$ is temperature, ${\displaystyle \dot{\epsilon }}$ is the uniaxial strain rate, ${\displaystyle {\sigma }_{creep}}$ is the creep stress, and for lithium metal ${\displaystyle m=6.6}$, ${\displaystyle Q_c=37\mathrm{k}\mathrm{J}\cdot {\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}}$, ${\displaystyle A_c^{-1/m}=3\times {10}^5\mathrm{P}\mathrm{a}\cdot {\mathrm{s}}^{-1}}$.

For lithium metal to be used as an anode, great care must be taken to minimize the cell pressure to relatively low values on the order of its yield stress of 0.8 MPa. The normal operating cell pressure for lithium metal anode is anywhere from 1-7 MPa. Some possible strategies to minimize stress on the lithium metal are to use cells with springs of a chosen spring constant or controlled pressurization of the entire cell. Another strategy may be to sacrifice some energy capacity and use a lithium metal alloy anode which typically has a higher melting temperature than pure lithium metal, resulting in a lower propensity to creep. While these alloys do expand quite a bit when lithiated, often to a greater degree than lithium metal, they also possess improved mechanical properties allowing them to operate at pressures around 50 MPa. This higher cell pressure also has the added benefit of possibly mitigating void formation in the cathode.

Advantages

Solid-state battery technology is believed to deliver higher energy densities (2.5x).

They may avoid the use of dangerous or toxic materials found in commercial batteries, such as organic electrolytes.

Because most liquid electrolytes are flammable and solid electrolytes are nonflammable, solid-state batteries are believed to have lower risk of catching fire. Fewer safety systems are needed, further increasing energy density at the module or cell pack level. Recent studies show that heat generation inside is only ~20-30% of conventional batteries with liquid electrolyte under thermal runaway.

Solid-state battery technology is believed to allow for faster charging. Higher voltage and longer cycle life are also possible.

Thin film solid state batteries

Background

The earliest thin film solid state batteries is found by Keiichi Kanehori in 1986, which is based on the Li electrolyte. However, at that time, the technology was insufficient to power larger electronic devices so it was not fully developed. During recent years, there has been much research in the field. Garbayo demonstrated that “polyamorphism” exists besides crystalline states for thin film Li-garnet solid state batteries in 2018, Moran demonstrated that ample can manufacture ceramic films with the desired size range of 1–20 μm in 2021.

Structure

Anode materials: Li is favored because of its storage properties, alloys of Al, Si and Sn are also suitable as anodes.

Cathode materials: require having light weight, good cyclical capacity and high energy density. Usually include LiCoO2, LiFePO4, TiS2, V2O5and LiMnO2.

Preparation techniques

Some methods are listed below.

• Physical methods:
  1. Magnetron sputtering (MS) is one of the most widely used processes for thin film manufacturing, which is based on physical vapor deposition.
  2. Ion-beam deposition (IBD) is similar to the first method, however, bias is not applied and plasma doesn't occur between the target and the substrate in this process.
  3. Pulsed laser deposition (PLD), laser used in this method has a high power pulses up to about 10⁸ W cm⁻².
  4. Vacuum evaporation (VE) is a method to prepare alpha-Si thin films. During this process, Si evaporates and deposits on a metallic substrate.
• Chemical methods:
  1. Electrodeposition (ED) is for manufacturing Si films, which is convenient and economically viable technique.
  2. Chemical vapor deposition (CVD) is a deposition technique allowing to make thin films with a high quality and purity.
  3. Glow discharge plasma deposition (GDPD) is a mixed physicochemical process. In this process, synthesis temperature has been increased to decrease the extra hydrogen content in the films.

Development of thin film system

• Lithium-Oxygen and Nitrogen based polymer thin film electrolytes has got fully used in solid state batteries.
• Non-Li based thin film solid state batteries have been studied, such as Ag-doped germanium chalcogenide thin film solid state electrolyte system. Barium-doped thin film system has also been studied, which thickness can be 2μm at least. In addition, Ni can also be a component in thin film.
• There are also other methods to fabricate the electrolytes for thin film solid state batteries, which are 1.electrostatic-spray deposition technique, 2. DSM-Soulfill process and 3. Using MoO3 nanobelts to improve the performance of lithium based thin film solid state batteries.

Advantages

• Compared with other batteries, the thin film batteries have both high gravimetric energy density and volumetric energy density. These are important indicators to measure battery performance of energy stored.
• In addition to high energy density, thin-film solid-state batteries have long lifetime, outstanding flexibility and low weight. These properties make thin film solid state batteries suitable for use in various fields such as electric vehicles, military facilities and medical devices.

Challenges

• Its performance and efficiency are constrained by the nature of its geometry. The current drawn from a thin film battery largely depends on the geometry and interface contacts of the electrolyte/cathode and the electrolyte/anode interfaces
• Low thickness of the electrolyte and the interfacial resistance at the electrode and electrolyte interface affect the output and integration of thin film systems.
• During the charging-discharging process, considerable change of volumetric makes the loss of material.